1. Field of the Invention
The present invention relates to a method for forming a fixing end portion of a composite rope used for suspending marine-transportation equipment or for anchoring a boat, as a cable for controlling an automobile or an aircraft, as a member for reinforcing a concrete structure or a structure which must be prevented from becoming magnetized, or a non-loosened member for reinforcing a cable. The present invention also relates to a composite rope having a fixing end portion used in combination with the above-mentioned rope, cable, or reinforcing member.
2. Description of the Related Art
U.S. Pat. No. 4,677,818, U.S. Application Ser. No. 427,171, Examined Japanese Patent Publications Nos. 57-25679 and 62-18679 disclose a technique of impregnating filaments having a high tensile strength and a low elongation with a thermosetting resin to manufacture composite ropes which are lighter in weight and more corrosion-resistant than wire ropes and have the substantially same tensile strength and elongation as the latter.
A composite rope is not only very light in weight and highly corrosion-resistant but also has a high tensile strength, a low extension, and a low relaxation. Because of these excellent physical and chemical properties, attempts have been made to use a composite rope as a tightening member for prestress concrete, pretension type concrete, and post-tension type concrete, and as an outcable, in place of a steel wire rope.
When the composite rope made of filaments having a high tensile strength and a low elongation, it is important to securely connect an end portion of the composite rope with a fixing member with ease, at a high accuracy and at a low cost.
Conventional, methods by which the ends of composite ropes are formed include an eye splicing method or a rope slicing method. These conventional methods, however, can be applied to easily loosened/flexible ropes but are not applicable to the above-mentioned composite ropes as hard unloosened/non-flexible.
According to another conventional fixing method, a wedge type cone (male cone) is directly fixed to an end portion of a rope and is inserted in a socket (a female cone), to connect the end portion with the socket. In the case of this third conventional method, however, a local shearing stress is directly applied from the cones to the composite rope, with the result that the composite rope can easily be broken at its fixing end portion. Thus, a required fixing strength cannot be obtained using this method. Further, since the composite rope is imperfectly stuck to the male cone, its diameter is reduced when a pulling force is applied thereto, with the result that it can easily be pulled out of the male cone.
Unexamined Japanese Patent Application No. Hei 1-272889 discloses a technique of coating, with a resin layer, an end portion of a composite rope to which a cone is fixed, in order to reduce the local shearing stress applied to the composite rope.
This method, however, has drawbacks in that it takes several days for the coating resin to fully cure, and the resin cannot with stand high temperatures.